Intermale aggression and infanticide in aged C57BL/6J male mice: Behavioral deficits are not related to serum testosterone (T) levels and are not recovered by supplemental T

Healthy aged adul (24–26 months of age) and young adult (2–4 months of age) C57BL/6J male mice were assessed for intermale aggression, pup-killing behavior (infanticide), and circulating levels of testosterone (T). When compared to young adult male mice, aged adult males were highly variable in the exhibition of both androgen-dependent behaviors. Significant numbers of aged males exhibited deficits in aggression and pup-killing while other animals were as behaviorally active as their young male counterparts. Assessment of serum T showed that aging did not produce a reduction in levels of the steroid and individual variability in androgen-dependent behavior of aged males was not related to plasma levels of the hormone. When aged non-aggressive and non-killer males were exposed to supplemental T by way of subcutaneously implanted silastic capsules, circulating levels of the steroid were elevated but T-dependent behavior was not recovered. These findings, in combination with those previously reported for copulatory behavior, indicate that the deficits observed in the androgen-dependent behavior of aged male mice cannot be attributed to a breakdown in the production of testicular androgens. While neural refractoriness to T may account in part for deficits in androgen-dependent behavior of aged males, the variability that is observed in the reproductive behaviors of aged male rodents ultimately may be related to other sources of variation such as perinatal environment.     

The great mimicker: Phenotypic overlap between constitutional mismatch repair deficiency and Tuberous Sclerosis complex

Constitutional mismatch repair deficiency is a rare cancer predisposition syndrome caused by biallelic mutations in one of the four mismatch repair genes. Patients are predisposed to various tumors including hematological malignancies, brain tumors and colorectal carcinomas. Phenotypic overlap with Neurofibromatosis-1 is well known, with most patients presenting with café-au-lait macules. Other common features include axillary and/or inguinal freckling and intracranial MRI foci of high T2W/FLAIR signal intensity similar to the typical FASI seen in Neurofibromatosis-1. In this cohort of eight patients with constitutional mismatch repair deficiency we describe overlapping phenotypical features with Tuberous Sclerosis complex. In addition to “ash-leaf like” hypomelanotic macules (five patients), we detected intracranial tuber-like lesions (three patients), renal cysts (three patients) and renal angiomyolipomas (two patients). All our patients also had Neurofibromatosis-1 like features, mainly café-au-lait macules. This study suggests that features of Tuberous sclerosis especially when overlapping with those of Neurofibromatosis 1 or malignancies atypical for these syndromes should raise the possibility of constitutional mismatch repair deficiency. Correct diagnosis is essential for appropriate genetic counseling and pre-emptive cancer surveillance.     

The Association of Teachers of Preventive Medicine's recommendations for postgraduate education in prevention

The Guide to Clinical Preventive Services, prepared in 1989 by the U.S. Preventive Services Task Force, assesses the effectiveness of 169 types of preventive interventions. In 1990, the Association of Teachers of Preventive Medicine formed a panel to review the guide and recommend ways it could be used to enhance both undergraduate and postgraduate medical education. This paper outlines the panel's recommendations of the types of knowledge and attitudes on which postgraduate medical education in prevention should be built. Detailed recommendations are presented, based on the summary findings of the guide, for residency education in prevention. Implementation of these recommendations will integrate preventive services into the continuum of medical care. These recommendations are presented to achieve the goal of educating physicians to approach the total patient, putting the patient's health rather than the disease process in the forefront of primary medical care.     

Biofluid Aspects of Embryo Transfer

Embryo transfer (ET) is the last stage of extracorporal fertilization during which the embryo is placed in the uterine cavity with a medium-filled catheter 2–3 days after in vitro fertilization. While fertilization in the laboratory occurs at very high rates (>:90%), the overall success of the procedure (i.e., take home baby) is still very low (<25%) and assumed to be mainly due to implantation failure. A computational model was developed to simulate ET within the uterine cavity by a fluid-filled catheter inserted into a two-dimensional channel with oscillating walls. The results showed that the speed at which the embryos are injected from the catheter dominates the procedure and controls the velocity of their transport within the uterine cavity. ET at excessively high injection speeds may lead to ectopic pregnancies, while uterine peristalsis affects transverse dispersion only during injection at low injection speeds. The presence of the catheter within the uterus does not affect flow patterns downstream of its tip. The potential risks to implantation failure due to mechanical factors involved in the ET processes are discussed. © 2003 Biomedical Engineering Society. PAC2003: 8719-j, 8710+e     

Coronary heart disease risk factors in black and white patients with non‐insulin‐dependent diabetes mellitus

Objective. To determine possible racial differences in risk factors for coronary heart disease (CHD) in black and white patients with noninsulin‐dependent diabetes mellitus (NIDDM).

Methods: Study of risk factors for coronary heart disease among 308 subjects who met the WHO criteria for NIDDM.

Results. Both black and white patients were found to have a high prevalence of hypertension, obesity, low high density lipoprotein (HDL) cholesterol, low leisure‐time physical activity levels, and an atherogenic dietary profile. Black males were more likely to have hypertension, reported a greater intake of dietary cholesterol, and had lower triglycerides, higher HDL cholesterol levels, a lower CHOL/HDL ratio, and a lower waist to hip ratio (WHR) than white males. Black females had higher mean arterial and diastolic blood pressures, had lower triglycerides, higher HDL cholesterol, a lower CHOL/HDL ratio, a higher subscapular/triceps ratio and lower reported leisure‐time energy expenditure compared to white females. There were no racial differences found for obesity level.

Conclusion. Our results indicate that racial differences in CHD risk factors exist among black and white patients with NIDDM. The complex genetic, sociocultural and environmental interactions involving CHD risk factors that contribute to the development of CHD may eventually provide clues to the etiology of the disease.     

Measurement of nerve dysfunction in neuropathic pain

Neuropathic pain is difficult to diagnose and treat. Both can be made easier if the nerve dysfunction can be quantified. The two basic modes of evaluation are subjective and objective. This article presents currently used methods in both arenas. Discussion is also given to some basic neurophysiology necessary to understanding the use of these testing methods.